Problem: Nadia is 5 times as old as Michael and is also 28 years older than Michael. How old is Nadia?
Answer: We can use the given information to write down two equations that describe the ages of Nadia and Michael. Let Nadia's current age be $n$ and Michael's current age be $m$ $n = 5m$ $n = m + 28$ Now we have two independent equations, and we can solve for our two unknowns. One way to solve for $n$ is to solve the second equation for $m$ and substitute that value into the first equation. Solving our second equation for $m$ , we get: $m = n - 28$ . Substituting this into our first equation, we get the equation: $n = 5$ $(n - 28)$ which combines the information about $n$ from both of our original equations. Simplifying the right side of this equation, we get: $n = 5n - 140$ Solving for $n$ , we get: $4 n = 140$ $n = 35$.